Anti-aircraft gunfire-control apparatus



J.-L. ROUTIN. ANTI-AIRCRAFT GUNFIRE CONTROL APPARATUS. APPLICATION FILED SEPLB. I917- 1,345,703. Patented July 6,1920.

3 SHEETS-SHEET l.

3 SHEETS-SHEEI 2.

(o l. b

J. L. ROUTIN.

ANTI-AIRCRAFT GUNFIRE CONTROL APPARATUS.

I APPLICATION FILED SEPLB. I917- 1,345,703. Patented July 6, 1920.

wmw u wm m WW new/mag? UNITED STATES PATENT OFFICE.

ANTI-AIRCRAFT GUNFIRE-CONTROL APPARATUS.

Specification of Letters Patent.

Patented July 6, 1920.

Application filed September 8, 1917. Serial No. 190,337.

To all whom it may concern:

Be it known that I, JOSEPH LOUIS Rou- TIN, a citizen of the French Republic, and a resident of 2 Rue Olchanski, Paris, France, have invented a new and useful Improvement in Anti-Aircraft Gunfire-Control Apparatus, which invention is fully set forth in the following specification.

The present invention relates to improvements in tachochronometrical apparatus such as described in my application for patent Serial No. 182,311, filed July 23, 1917, now Patent No. 1,345,697, dated July 6, 1920, and has for its object to provide a particular form of apparatus of the above kind which permits of the direct determination of the product of either the azimuthal or zenithal velocity of an aerial target by the time of flight of the projectile without making any calculations, it being assumed that the aerial target is moving at a constant altitude during the time of flight of the projectile.

In regulating the firing of anti-aircraft guns, it is necessary to apply a correction to the vertical and lateral. directions of aim in order to compensate for the change of position of the aerial target during the time of flight of the projectile. This correction requires the determining of the angular zenithal and azimuthal. velocities of the target and a knowledge of the time of flight of the projectile for an extrapolated or estimated distance of the target. Representing the zenithal angle by a, the azimuthal angle by m, and by f, the time of flight of the projectile corresponding to the range taken at 25 or the time of taking the readings for distance D to the aerial target, the zenithal and azimuthal velocities will be expressed by and respectively.

Knowing at the time i=0 when the readings are made, the angle of sight a the altitude H of the objective, its azimuthal angularspeed and its zenithal angular speed -35? to determine the corrections to be H and 0a,, are known. Designating the duration of flight by 7%, it is evident that the correction c to be made in the vertical aim and the correction 8, the dihedral angle formed by the two planes of sight, to be made 1n the direction pointing, are given wltlh sufiicient approximation by the formu 2e As the altitude varies rather slowly, it can, on the other hand, be assumed that the future distance D is defined by the intersectlon with the horizontal plane, of altitude H with the line of aim making with the horizon an angle in which formula t, represents the time lost or required for reading the range D and angle of height a fix the elevation, correct the ad ustment of the telescope in relation to the arms of the gun and regulate the fuse and load the gun.

In order that the invention may be more readily understood, reference is had to the accompanying drawings, in which Figure 1 is a diagrammatic view showing how zenithal and azimuthal corrections 0 and 5 and the future distance D may be obtained directlywithout making any calculation;

Fig. 2 is a view showing a scale of time of flight curves which give the values f for heights H and angles a and are determined by data from tables of firing; and

Fig. 3 is a view showing a scale of curves giving data for the fuse-setting known to French engineers as distances debouchoir or issuing distances in functions of altitude H and of the future sight Referring to Fig. 1 of the drawings, 1 is a handle which serves to move the vertical aiming telescope 2 by means'of the screw 3 and the sector 4. This handle also operates the armature coil 5 of a small continuous current magneto, as well as two scale-carrying drums 6 and 7 so mounted as to make a complete revolution when the telescope is displaced through 90. The drum 7 can also be displaced by means of the difierential 8 by operating the handle 9 by hand. Any magneto or small continuous current generator, capable of impressing on a very large and practically constant resistance a difference of potential proportional to the speed of rotation, is suitable for the purpose.

10 and 11 are two indexes which can be moved along two scales parallel to the axes of the drums. The position of the indexes is regulated according to the indication of the altitude. On drum 6 is placed the scale of curves representing the duration of flight f shown inFig. 2, and on drum 7 is placed the scale of curves representing future distances D or the distances debouchoir shown in Fig. 3.

The duration of flight f is read directly on the drum 6 opposite index 11.

12 is a resistance connected with the brushes of generator 5 and used as a potentiometer to enable the zenithal correction o to be read on the voltmeter 13 when the movable contact 14 is placed in front of the graduation corresponding to 7%. The indexhand of the voltmeter 13 responds to the voltage across the brushes of the current generator and this voltage is proportional to the speed of its armature and in turn to the angular speed of the aerial object. The index-hand also responds to the fall of potential along the resistance 12 and this is made proportional to the time of flight 7",, as determined by the reading on drum 6. The resultant movement of the index-hand depends, therefore, jointly on the product da at which may be directly read off on the voltmeter by aid of proper graduations.

The movable contact 15 being integral with sliding contact 14 and in advance of 15 on the latter, the value of the angular correction 1 (mo o is indicated on the suitably graduated voltmeter 16.

This angle having been transmitted to the drum 7 by operating the handle 9, the future distance D is read opposite the index 10. It is generally preferable to carry on the drum 7 not the values of the extrapolated or future distances D but those of the issuing distances D which are functions of H and of future sight (1 a a (j; +f o.

D is really a graduation which is used in set ting the time fuse and difiers slightly in value from the future distance D The calibration of the voltmeters l and 16 to obtain, directly on the scale of the voltmeters, corrections in milliemes or mills is secured by operating the movable contact 17. It also enables restandardizing the voltmeters in case the intensity of the magnetic field of the generator should vary.

The whole of the device represented in Fig. 1 is involved in the movement transmitted to the direction aiming telescope as explained in the principal application above referred to. The value of the azimuthal correction 3 is obtained by use of a similar apparatus to that above described, by setting on the graduation f the movable contact of the potentiometer connected to the current generator of the direction aim.

The device described has further the great advantage of allowing the direct determination of the correction of the direction aim, even in the case (which is rather frequent) of the aiming devices mounted on the barrel only permitting this correction to be made by displacing the telescope in the plane of sight. The value of the correction is then given by the formula: 4

It is consequently seen that it is suflicient to draw on the drum 6 a second series of curves (of different colors) giving directly seconds and enabling one to regulate the time of the firing.

It is evident that without altering anything in the principle of the apparatus the scales could be arranged in any other way by using, for instance, disks in the place of the cylinders 6 and 7 As the movement to be given to the fingers of the potentiometer 1s only a function of angle of sight and of the altitude, the index 11 could be further connected mechanically to the contacts 14 and 15 and scales graduated in functions of altitude drawn on the drum or disk 6. This may be accomplished in the following manner: On the drum 6 are placed a set of equi-height curves H 21; H 2, etc., having for their coordinates angles of sight a and times of flight 7%. It will suflice, then, to maintain the index 11 on the curve H corresponding to the altitude announced. Contacts 14 and 15 having a suitable mechanical connection with index 11 will therefore be moved proportionally to the values of the terms of flight.

Finally the magnetos of the potentiometers and the voltmeters could be replaced by any tachometers, mechanical or magnetic, suitable for the purpose.

Where reference is made to the angle of sight, this refers to both the vertical and the horizontal angle and the claims are to be so interpreted.

What is claimed is 1. In apparatus of the character described, where the target is moving at a constant altitude during the time of flight of the projectile, the combination of a tachometer giving the angular speed of the target with two scales one giving the time of flight and the other the issuing distance in functions of the angle of sight and of the altitude (H 2. A form of construction of the apparatus in claim 1 applicable when the sighting device is arranged so that the correction is given in the plane of sight characterized by the drum indicating the time of flight being provided with a series of curves indicating the duration of the fictitious time of flight which should be taken into consideration and which are given by the product of the duration of the actual time of flight (t by the cosine of the angle of sight 1 3. In apparatus for regulating the firing of anti-aircraft guns where the target is moving at a constant altitude during the time of flight of the projectile, the combination of two movable supports responsive to theangular movements of a sighting device, one of said supports being provided with a set of curves giving times of flight of the projectile and the other with a set of curves giving fuse-setting distances, heightindicating indices adjustable in relation to said curves, a tachometer adapted to respond to the angular speed of the target and to the time of flight of the projectile and'to indicate the product of the two factors, and means for applying such product to the fusesetting distances indicated by said fuse-setting curves.

4. In apparatus for regulating the firing of anti-aircraft guns where the target is moving at a constant altitude during the time of flight of the projectile, the combination of two movable supports responsive to the angular movements of a sighting device, one of said supports being provided with a set of curves giving times of flight of the projectile and the other with a set of curves giving fuse-setting distances, height-indicating indices adjustable in relation to said curves, asource of potential responsive to the speed of the target, a voltmeter in circuit therewith, and means for varying the voltage through the meter proportional to the time of flight of the projectile, and means for moving the support provided with fuse; setting curves in accordance with the indications by said voltmeter.

In testimony whereof I have signed this specification.

JOSEPH LOUIS ROUTIN. 

